feat: add social features, leaderboard, auth enhancements, and admin fixes

- Implement Social Features: Shared Tasks, Global Access, Privacy Settings (Leaderboard/Searchable).
- Add Leaderboard Page and API.
- Enhance Auth: Support Email/Username login, explicit duplicate registration errors.
- Fix: Admin login password hash regression.
- Refactor: Move to wouter for routing, add Admin Dashboard and User Management.
- Add Setup Wizard.
- Update UI with Sidebar and Gamification elements.

client/src/index.css

@@ -48,7 +48,8 @@
 
   --popover-border: 220 13% 85%;
 
-  --primary: 210 100% 56%;
+  /* Premium Violet/Indigo Base */
+  --primary: 250 95% 64%;
 
   --primary-foreground: 210 17% 98%;
 
@@ -76,10 +77,11 @@
   --chart-4: 43 74% 66%;
   --chart-5: 27 87% 67%;
 
-  --font-sans: Inter, Open Sans, sans-serif;
+  --font-sans: "Inter", sans-serif;
+  --font-heading: "Outfit", sans-serif;
   --font-serif: Georgia, serif;
   --font-mono: Menlo, monospace;
-  --radius: .5rem; /* 8px */
+  --radius: 1rem; /* 16px - Softer look */
   --shadow-2xs: 0px 2px 0px 0px hsl(220 13% 91% / 0.00);
   --shadow-xs: 0px 2px 0px 0px hsl(220 13% 91% / 0.00);
   --shadow-sm: 0px 2px 0px 0px hsl(220 13% 91% / 0.00), 0px 1px 2px -1px hsl(220 13% 91% / 0.00);